function setCookie(cname,cvalue,exdays)
{
    var d = new Date();
    d.setTime(d.getTime()+(exdays*24*60*60*1000));
    var expires = "expires="+d.toGMTString();
    // 需要设置相同路径才能在不同页面获取到cookie
    document.cookie = cname + "=" + cvalue + "; " + expires + ";path=/";
}

function getCookie(cname)
{
    var name = cname + "=";
    var ca = document.cookie.split(';');
    for(var i=0; i<ca.length; i++)
    {
        var c = ca[i].trim();
        if (c.indexOf(name)==0) return c.substring(name.length,c.length);
    }
    return "";
}